This description relates to automated metrology, and, more particularly, to methods and systems for generating a view plan for features to be measured, implementing the view plan to generate view data, and analyzing the view data to generate dimensional data for the features.
At least some known methods of determining whether a feature, such as, a cooling hole in a turbine blade meets dimensional requirements is to gauge the feature using a measuring tool, such as, a pin gauge. As used herein, dimensional requirements refer to size, spacing and distance characteristics of features of an object, for example, a turbine blade or other workpiece. However, cooling holes are being formed with more complex designs that require more complete hole and diffuser area mapping. Overall airflow tests are done on airfoils, but this only provides a test of the volume of air and does not necessarily provide a good mapping of the cooling performance of the holes. Various measurement methods including X-ray computed tomography (CT), in-line and triangulation laser point probes, touch probe methods, and structured light based 3-D optical methods have been attempted with only limited success. X-ray CT is able to see the holes, but does not have the resolution to map very small holes accurately enough to verify the dimensional measurements meet manufacturing or maintenance specifications. Point-probing methods, either optical or touch, require some form of mechanical scanning of the probe. The need for mechanical scanning introduces challenges in terms of access to the hole, fitting into the hole, and speed. To improve the speed using point probing, often an assumption is made that the holes are round and centered. In this manner, only a limited number of profiles need to be taken. However, this assumption may not be correct to the level of tolerance of the hole geometry needed for best cooling. Other microscopic methods using specific focus planes provide an incomplete map of the hole which can miss key transition points of interest unless the time is taken for many more focus planes.